Mycotoxin sequestering agent: Impact on health and performance of dairy cows and efficacy in reducing AFM1 residues in milk.

The objectives of this study were to evaluate the exposure to a diet naturally contaminated with mycotoxins on lactation performance, animal health, and the ability to sequester agents (SA) to reduce the human exposure to AFM1. Sixty healthy lactating Holstein cows were randomly assigned to two groups: naturally contaminated diet without and with the addition of a SA (20 g/cow/d AntitoxCooPil® -60% zeolite-40% cell wall-). Each cow was monitored throughout lactation. The concentration of aflatoxin B1 (AFB1) in feed and M1 (AFM1) in milk, health status, and productive and reproductive parameters were measured. AFB1 concentration in feed was very low (2.31 µg/kgDM). The addition of SA reduced the milk AFM1 concentrations (0.016 vs. 0.008 µg/kg) and transfer rates (2.19 vs. 0.77%). No differences were observed in health status, production and reproduction performance. The inclusion of SA in the diet of dairy cows reduce the risk in the most susceptible population.

Performance of Autumn and Spring Calving Holstein Dairy Cows with Different Levels of Environmental Exposure and Feeding Strategies.

Environmental exposure during confinement and feeding strategy affects cow behavior, nutrient utilization, and performance. Milk production and composition, body condition score, non-esterified fatty acids, and beta-hydroxybutyrate were determined during a full lactation in cows submitted to (a) grazing + partial confinement in outdoor soil-bedded pens with shade structures (OD-GRZ); (b) grazing + partial confinement in a compost-bedded pack barn with cooling capacity (CB-GRZ); or (c) total confinement (same facilities as CB-GRZ) and fed TMR ad libitum (CB-TMR). Autumn (ACS) and spring (SCS) calving season cows were used for each treatment, except for CB-TMR (only SCS). In ACS, treatments did not differ in any variable, possibly due to mild weather. In SCS, milk production was higher in CB-TMR than CB-GRZ, which in turn produced more milk than OD-GRZ. Differences coincided with heat waves and/or heavy rains (similar grazing conditions and mixed ration DM intake). Milk fat, protein and lactose yield, protein content, and BCS were higher in CB-TMR, without differences between CB-GRZ and OD-GRZ. Cows in OD-GRZ had impaired energy metabolism. Under moderately unfavorable environmental conditions (ACS), when well-managed, OD-GRZ systems could equate to the productive response of CB-GRZ. However, in worse climatic conditions (SCS), performance could be compromised, especially when compared to TMR systems.

The effect of feeding inorganic and organic selenium sources on the performance and content of selenium in milk of transition dairy cows

The aim of this study was to determine the effects of supplementing close-up and fresh dairy cows diets with sodium selenite or organic sources of selenium (Se) on the dry matter intake (DMI), milk production and composition. Based on their body condition score (BCS), previous lactation milk yield and expected calving date, 24 multiparous Holstein dairy cows were balanced and randomly assigned to 4 experimental treatments. Experimental treatments were: control (basal diet without Se supplementation with 0.10 and 0.15 mg of Se kg-1 DM in close-up and fresh diets, respectively), sodium selenite supplementation (0.50 mg of Se kg-1 DM; Se-S), selenium yeast supplementation (0.50 mg of Se kg-1 DM; Se-Y) and selenomethionine supplementation (0.50 mg of Se kg-1 DM; Se-M). Neither Se supplementation nor Se source affected DMI pre- and postpartum. Milk production and composition were not different across Se sources, but concentrations of Se in milk were 14 and 10% greater for cows fed Se-M and Se-Y than for those fed control, respectively. Cows fed Se-M had lower somatic cell count than control (SCC; 173.11 vs. 318.89 cells × 103 Ml-1). The changes of BW and BCS pre- and postpartum were not affected by treatments over experimental period. The results of present study showed that selenomethionine supplementation compared to other sources decreased SCC in transition cows. In addition, milk Se concentrations increased in Se-Y and Se-M groups more significantly compared to the Se-S group. This indicates that organic Se had better replace inorganic Se for transition dairy cows.(AU)

The effect of feeding inorganic and organic selenium sources on the performance and content of selenium in milk of transition dairy cows

The aim of this study was to determine the effects of supplementing close-up and fresh dairy cows’ diets with sodium selenite or organic sources of selenium (Se) on the dry matter intake (DMI), milk production and composition. Based on their body condition score (BCS), previous lactation milk yield and expected calving date, 24 multiparous Holstein dairy cows were balanced and randomly assigned to 4 experimental treatments. Experimental treatments were: control (basal diet without Se supplementation with 0.10 and 0.15 mg of Se kg-1 DM in close-up and fresh diets, respectively), sodium selenite supplementation (0.50 mg of Se kg-1 DM; Se-S), selenium yeast supplementation (0.50 mg of Se kg-1 DM; Se-Y) and selenomethionine supplementation (0.50 mg of Se kg-1 DM; Se-M). Neither Se supplementation nor Se source affected DMI pre- and postpartum. Milk production and composition were not different across Se sources, but concentrations of Se in milk were 14 and 10% greater for cows fed Se-M and Se-Y than for those fed control, respectively. Cows fed Se-M had lower somatic cell count than control (SCC; 173.11 vs. 318.89 cells × 103 Ml-1). The changes of BW and BCS pre- and postpartum were not affected by treatments over experimental period. The results of present study showed that selenomethionine supplementation compared to other sources decreased SCC in transition cows. In addition, milk Se concentrations increased in Se-Y and Se-M groups more significantly compared to the Se-S group. This indicates that organic Se had better replace inorganic Se for transition dairy cows.

Lactation performance of Holstein cows treated with 2 formulations of recombinant bovine somatotropin in a large commercial dairy herd in Brazil.

The objectives of this controlled study were to compare the effects of 2 different formulations of recombinant bovine somatotropin (rbST) on milk yield, milk composition (fat and protein), milk somatic cell count, and body condition score (BCS) among dairy cattle in a large commercial herd. Regulatory approved 500-mg zinc sesame oil base rbST (ZSO-rbST; Elanco Animal Health, Greenfield, IN) and vitamin E lecithin base rbST (VEL-rbST; LG Life Sciences, Seoul, South Korea) formulations were administered per the manufacturers' recommendations every 14 d over 17 injection cycles starting at 57 to 70 d of lactation (90 cows per rbST group). Control cows (n = 60) received no rbST. Somatotropin-treated animals (VEL-rbST and ZSO-rbST combined) had increased average milk yield and protein percentage and lower average BCS compared with control cows. For primiparous cows, average milk yield was 37.75 kg/d with the ZSO-rbST treatment and 35.72 kg/d with the VEL-rbST treatment. For multiparous cows, average milk yield was 40.13 kg/d with the ZSO-rbST treatment and 38.81 kg/d with the VEL-rbST treatment. There were no differences in milk fat percentage between VEL-rbST and ZSO-rbST treatments, but milk protein content was greater with VEL-rbST treatment than with ZSO-rbST treatment. Nonetheless, cows treated with ZSO-rbST yielded more kilograms of fat and protein per day than cows treated with VEL-rbST. No significant differences in BCS were found between both rbST treatment groups. The differential increase in milk yield between cows treated with ZSO-rbST and VEL-rbST was driven by rbST response differences both within the 14-d cycle and throughout the 17 injection cycles. The cows treated with VEL-rbST demonstrated a more variable 14-d milk yield response curve, with more pronounced valleys between injections compared with the ZSO-rbST formulation. In addition, only the ZSO-rbST treatment was effective in modifying the lactation persistency compared with control cows. Compared with the VEL-rbST formulation, the ZSO-rbST formulation yielded more kilograms of milk, fat, and protein with less milk variation throughout the seventeen 14-d lactation cycles for both primiparous and multiparous cows.